Although the index search UI only shows a single search box it's still possible to search on different file attributes by prefixing with a field identifier, e.g.
name: - Search on the name of the item.
lookin: - Search on the location of the item.
ext: - Search on the file extension.
moddt: - Search on the modified date of the item.
createdt: - Search on the created date of the item.
size: - Search on the size of the item.
For more information please see:
Future plans include UI elements to help enter the criteria.